Dear Editor,
I note in my latest Personalised Report, “The medical management of
stable angina”, that you monitor the frequency of my lipid testing.
It has been my custom not to continue annual (or more frequent) testing, on patients who have been established on statins
with good therapeutic response, in the belief that once the lipids were stable on a particular dose of statin, the blood
profile would not change significantly, that is, unless a patient were to go on a fish-and-chips binge!
Blood pressure tends to drift up with age and warrants intermittent testing, even for those patients well controlled
on antihypertensives. This I understand. Will lipids drift upwards too, even if once successfully controlled on statins?
That is: is frequent re-testing (yearly or more frequent) necessary for this group of patients, as you seem to imply
in your report?
Incidentally, in patients with initially good lipid profiles, I don’t retest frequently in the belief that, similarly,
unless their dietary habits changed drastically, their lipid profile would be unlikely to change in the short term. I
tend to retest such patients after the passage of 4-5 years.
Am I out of step with recommended practice on these points? On the one hand, I don’t want to neglect my patients.
On the other, I see no point in frequently re-testing a stable lipid profile if it is unlikely to change in the short
to medium term.
Dr Alan Kenny, General Practitioner
Tokoroa
It is appreciated that the clinical judgement of the General Practitioner and the patient’s preference are likely
to guide the need for re-testing on an individual basis, however, when developing a guideline, report or article, advice
must apply to populations.
Current New Zealand guidelines recommend annual risk assessment for patients on lipid modification.1 An
annual fasting lipid test may be used to monitor the success of statin treatment and to check and enhance compliance.2 It
may also be used to trigger a discussion with the patient about their ongoing commitment to a low cholesterol diet,
weight management and a regular exercise programme. Although these lifestyle factors can be incorporated into any consultation,
some patients may be more inclined to listen and act on preventative health care advice if there is a target to achieve
or a “bad” result to contemplate.
If a patient has achieved a “good therapeutic response” with statin treatment, annual lipid monitoring
may not necessarily help to reduce their cardiovascular risk. However, this relies on several factors - the patient
must:
- Remain compliant with statin treatment
- Continue to exercise regularly
- Make no major detrimental changes to their diet (i.e. avoid the fish and chips)
- Stay at a stable body weight
- Not develop any additional health problems that may influence exercise, diet and weight (such as osteoarthritis,
depression or a respiratory condition)
If statins are used for primary prevention (rather than secondary prevention such as in a patient with stable angina),
annual lipid testing is unnecessary.3
There is no evidence that lipid levels increase with age. However, it may help to consider the following points from
an Australian study which assessed patients at high risk of cardiovascular events on their knowledge and attitudes about
cholesterol and lipid lowering treatment. The study found that:4
- 67% of patients knew their most recent cholesterol level
- Of these patients, 69% had a total cholesterol level > 4.0 mmol/L
- 25% of patients were non-compliant with their lipid lowering medicine and 9% of this group thought they did not
have to take their medicine because their cholesterol was “under control”
- Although the majority of patients were aware of the importance of a healthy lifestyle, 85% found lifestyle changes,
such as a healthier diet and exercise, challenging
- Only 16% correctly identified high cholesterol as an important modifiable risk factor for cardiovascular disease
References
- New Zealand Guidelines Group (NZGG). New Zealand cardiovascular guidelines handbook: a summary resource for primary
care practitioners. 2nd ed. Wellington: NZGG; 2009.
- Doll H, Shine B, Kay J, et al. The rise of cholesterol testing: how much is necessary? Br J Gen Pract 2011;61(583):e81-8.
- National Institute for Health and Clinical Excellence (NICE). Lipid modification. NICE, 2008. Available from: www.nice.org.uk (Accessed
Nov, 2011).
- Carrington M, Retegan C, Johnston C, et al. Cholesterol complacency in Australia: time to revisit the basics of
cardiovascular disease prevention. J Clin Nurs. 2008;18(5):678-86.